Drafting pens



May 12, 1959 k w. w. ANDERSON DRAFTING PENS Filed Oct.

' INVENT WALTER WILLIAM NDERSON gTTdRNEYS r; DRAFIING PENS Walter William Anderson, Warley Woods, Birmingham, England Application October 10, 1955, Serial No. 539,576

1 Claim. or. 120-426) This invention relates to drafting pens for use in making any climate prints, free hand poster work, artistic and mechanical drawings.

In existing drafting pens constant cleaning is required to remove obstructing coagulated ink and this cleaning would eventually impair the efiiciency of the blades as same are liable to be damaged, distorted, worn, blunted, or dull so that fine work becomes impossible. Also supply of ink is limited so that constant refilling is necessary and results in great inconvenience to the draughtsman. Furthermore in existing drafting pens the ink ordinarily flows too freely and results in bulbs and overruns at the ends of the lines. Existing drafting pens are sharpened periodically so that maintaining the correct shape of the points of the blades is very difiicult. With present drafting pens feeding of ink to the apices of the points of the blades is irregular and therefore the ink will not flow properly to the apices and may even arch up so that starting of each line being drawn is provokingly difiicult. Also in conventional drafting pens the adjusting screw is awkwardly situated in close proximity to the points of the blades so that fingers are readily soiled and the adjustment of the blades is also hidden by the users own hands during such adjustments.

Thus it is an object of the present invention to overcome all the aforementioned difficulties and disadvantages.

It is one of the objects of the present invention to provide a drafting pen wherein means is afiorded for preventing coagulation of the ink.

It is another object of the present invention to provide a drafting pen wherein means is afiorded whereby the blades may be cleaned during use without interfering with or changing the width of the line being drawn and simultaneously with such cleaning the points of the blades will be automatically shaped to ensure that during use and wear the points of the blades will be efficiently maintained whereby the Width of the lines will remain unaffected throughout the life of the drafting pen.

It is a further object of the present invention to provide a drafting pen wherein means is afforded whereby the feeding of the ink to the apices of the points of the blades is controlled and determined whereby efficient starting of each line is obtained.

It is yet an object of the present invention to provide a drafting pen wherein the supply of ink available between the blades is much larger than was heretofore obtainable thereby reducing the number of refilling operations required while the width of each line is independent from the supply of ink available in the blades whereby little attention is required to the supply of ink available.

It is yet a further object of the present invention to provide a drafting pen wherein the ink is shielded from the outside air and continuously fed to the blades so that coagulation of the ink is substantially prevented.

It is still a further object of the present invention to provide a drafting pen adapted for equally making lines of very fine and also coarse or heavy widths and with ice j 2 a the width of each line being independent from the supply of ink available.

It is still another. object of the present invention to provide a drafting pen having means for feeding the ink in such manner that flow of ink is regulated so that, bulbs and overruns at the ends of the lines are automatically eliminated.

It is yet another object of the present invention to provide a drafting pen having means whereby there are obtained lines of greater length and width than where,

heretofore possible with. each single charge of ink.

It is a further object of the present invention to provide a drafting pen having means whereby the quantity of ink deposited from pen to paper or the like is reduced to a minimum and results in quicker drying of each line of ink and in each line having a substantially uniform a drafting pen wherein all the parts are removable separable and interchangeable and can be made economically as well as adapted to be modified for different requirements to which it maybe subjected.

'Having regard to these and other such advantages as may be obvious to anyone skilled in the art wenow refer to the drawings:

Figure 1 is a longitudinal section through the drafting pen constructed according to the invention.

Figure 2 is a fragmentary view of the end of the blade as viewed at right angles to Figure l.

The drawing pen in accordance with the invention comprises the combination of a tubular handle, a pair of resilient nibs at one end of the handle, a blade extending from between the nibs into the handle, and a spring loaded plunger forming part of or connected to the blade and extending from the end of the handle remote from the nibs, whereby the blade may be reciprocated between the nibs.

In the illustrated example there is fitted in one end of a tubular handle 3, a sleeve 4 carrying a pair of resilient metal nibs 5. These nibs 5 are so formed that their points are held together by their inherent resilience. Between the nibs is the one end of a blade 6 which may be connected to, but preferably (as shown) forms part of a plunger 7 which is slidable in the handle and extends from the end of the handle remote from the nibs.

Surrounding a portion of the plunger within the bandle, is a coiled compression spring 8, one end of which bears on a washer resting on the end of the sleeve 4 or any other fixed part in the handle, and the opposite end of which bears against an abutment 9 on the plunger.

The plunger 7 extends through a bore in an externally screw-threaded bushing 10, which engages in a screw threaded end of the handle 3, and is provided externally of the handle with a knurled head 11. The inner end of the bushing 10 normally bears against the abutment 9 and limits outward movement of the plunger under the action of the spring 8. The outer end of the plunger may be screw threaded to receive a knob 12.

The arrangement is such that when the plunger is depressed the blade 6 is moved outwardly between the points of the nibs 5 to remove congealed ink therefrom, the retraction of the blade and plunger being elfected by the spring 8.

The thickness of the line to be drawn is determined by the pressure between the points of the two nibs and this, in turn, is determined by the amount by which the blade 6 projects between the nibs. To adjust the thickness of the line to be drawn it is; therefore, only necessary to rotate the head 11' to adjust the bushing 10 inrelationto the handle, since the bushing: determines the amount by which the blade can be retracted by the spring.

Itmay be desirable fol" theWipof the bladei- 6 to have a slot 13 formed in it (as shown in FigureZ)" to aid th'e free fiowof -ink to thenibsb A lso to' prevent ink enteringthe-handIea'rubher" or other seal 14 is disposed be tween the blades; and is' held in position by a U-shaped clip"15 the limbs ofwliichenter-and areretained witliin the sleeve 4, the intermediate part of" this clip and-the seal 1% having holes through whichthe blade-canslide.

In order to-admit the'nibsbeing reset readily for a requii'ed thickness of line after they' havebeen set for-a difierentthiekness a circumferentiallyextending scale rn'ay be-provid'ed' on' the -head 11 of the bushing'or 'onthe adjacent end of the handle which'can'be read against an index mark on the complementarypart in the-manner of a'vernier screw gauge:

Having thus described an embodiment-of the invention it will be obvious to anyone-skilled in theartthat such" is'susceptihle: of further modifications: and'the scope of theinventiorris to be determined by the claim below in conjunction with the principles of operationandthe" mechanismofthe invention set forth above:

What is claimed is:

A draftingpen comprising a handle having' a longitudinally' extending boretherethrough; a sleeve" fixedly mounted" within one endiportion of said handle bore and extending therefrom forming an abutment within said bore, a pair of opposingresilienfnibs connectedto said 4 sleeve resiliently biasing the free tips of said nibs together and extending longitudinally of saidiholder,;said handle having threads provided in the opposite end portion of said bore, a threaded-tubular bushing extending within said handle bore and being in threaded engagement With said bore threads for being adjustably positioned within said handle and forming a second abutment in said handle bore, a plunger slidably extending through said bushing, said handle bore and said sleeve, a blade connected to and extending from one end of said plunger longitudinally oft-and between said nibs; fort at times being inserted betwe'e'n the tip's of-said nibs for removing foreigmmatter from-betweenwthesame, said plunger having an abutment positionedwithin saidliandl e bore and adjacent said bushing and a coillsprin'garound said plunger positioned between said plunger abutment and said sleeve abutment normally retaining said plunger abutment against said bushing abutment with said blade positioned thereby withdrawn'from between the' tips of 'said nibs;

References Cited in the fileof this patent UNITED STATES PA- FEN'TS 

